Membrane-localized expression, production and assembly of Vibrio parahaemolyticus T3SS2 provides evidence for transertion

It has been proposed that bacterial membrane proteins may be produced via 'transertion', or concurrent transcription, translation and membrane insertion from membrane-associated genes. Here, Kaval et al. provide evidence supporting that Vibrio parahaemolyticus uses transertion to assemble a transmembrane complex (type III secretion system) used to inject virulence factors into host cells. It has been proposed that bacterial membrane proteins may be synthesized and inserted into the membrane by a process known as transertion, which involves membrane association of their encoding genes, followed by coupled transcription, translation and membrane insertion. Here, we provide evidence supporting that the pathogen Vibrio parahaemolyticus uses transertion to assemble its type III secretion system (T3SS2), to inject virulence factors into host cells. We propose a two-step transertion process where the membrane-bound co-component receptor (VtrA/VtrC) is first activated by bile acids, leading to membrane association and expression of its target gene, vtrB, located in the T3SS2 pathogenicity island. VtrB, the transmembrane transcriptional activator of T3SS2, then induces the localized expression and membrane assembly of the T3SS2 structural components and its effectors. We hypothesize that the proposed transertion process may be used by other enteric bacteria for efficient assembly of membrane-bound molecular complexes in response to extracellular signals.

Automated summary

It has been proposed that bacteria use a process called transertion to synthesize and insert membrane proteins. This study provides evidence that Vibrio parahaemolyticus uses transertion to assemble its type III secretion system and inject virulence factors into host cells.